Casing and drill pipe protectors



Aug 14, 1956 A. w. KAMMERER, JR

cAsNG AND DRILL PIPE PRoTEcToRs Filed Aug. 9, 1954 0 2 i 4 5 a s 8 2 v d.5 www w m M D /f/ mm Y c AM v7 2 2 v/Lw C 3 a n I 7 8 L5 a 0 0 531 a e2 ii; w 2 \\A\/ Alec/f5@ WnMMf/ee efe.

United States Patent() CA'sING AND DRILL PIPE PRorEcToRs Archer W.Kammerer, Jr., Fullerton, "Calif., assiguor to Rotary Oil Tool Co.,Huntington Park, Calif., a cor` poration of 'California ApplicationAugust 9, 1954, Serial No. 448,459

'2 Claims. (Cl. Z55- 28) The present invention relates to devices forprotecting tubular drill strings during the rotary drilling of boreholes.

In the drilling of bore holes, rubber protectors have been mounted atspaced intervals on the exterior of strings of drill pipe, to preventthe latter from bearing against surface casing and other strings ofcasing in which the drill pipe is rotating. It is only desirable to havethe protectors disposed along that length of the drill pipe located inthe cased portion of the hole. Accordingly, in running drill pipe in thehole care must be exercised in accurately measuring the pipe, to insurethat the pipe stands with protectors thereon will be incorporated in thedrill string at the proper place, the protectors being located withinthe cased portion of the hole during the drilling operation.

Errors in measurement will result in the provision of inadequateprotectors in the cased portion of the hole, or the disposition ofrubber protectors in open hole, where the protectors are readily tornand inadvertently removed from the drill pipe by the open formation,which tends to restrict circulation of the drilling mud and possiblyproduces sticking of the drill pipe. Even with proper measurements, oneor more of the protectors may be moved down below the cased hole andinto open hole as drilling proceeds, produc-ing the aforementionedhazards.

The present practice of providing protectors on drill pipe is a timeconsuming and costly one. Not only must careful measurements be made ofthe unprotected drill pipe sections to be run in the open hole, but thedrill pipe sections fitted with protectors must be handled and storedseparately. The protectors are placed on the drill pipe by special toolsand must be cut oft the drill pipe when the latter is to be used withoutprotectors, or where a replacement protector is required.

Some bore holes are drilled by attaching a rotary drill bit to a stringof well casing, rather than to drill pipe. Attempts to put rubberprotectors on relatively large diameter drill casing would becomparatively costly, because of the size of the protectors, and suchprotected casing would be subject to the same disadvantages as drillpipe with protectors mounted thereon.

Accordingly, it is an Iobject of the invention to provide a protectivedevice for a tubular drill string that eliminates the need formeasurements of the drill string sections as they are being run in thehole, and the special storing and handling of the sections to be used inthe cased portion of the hole. The sections or stands of drill stringcan be run in the hole with-out regard to the length of the cased hole.

Another object of the invention is to provide a protective device for atubular drill string, in which the device cannot be disposed below thecased length of the hole, thereby preventing damage to the protect-ivedevice which would result were it disposed and used in Iopen hole.

A further object of the invention is to provide a protective device fora tubular drill string that provides a ice greatly increased bearing andprotective service, increasing greatly the life of the protectivedevice.

Yet another object of the invention is to provide a protective devicethat can be employed economically and with great effectiveness inconjunction with casing used as a drill string in drilling the borehole.

This invention possesses many other advantages, and

.has other objects which may be made more clearly apparent from aconsideration of several forms in which it may be embodied. Such formsare shown in the drawings accompanying and forming part of the presentspecification. These forms will now be described in detail, illustratingthe general principles of the invention; but it is to be understood thatsuch detailed description is not to be taken in a limiting sense, sincethe scope of the invention is best defined by the appended claims.

Referring to the drawings:

Figure l is a longitudinal section, with parts shown in elevation, of acased portion of the hole, embodying several forms of the invention,with a drill string disposed therein;

Fig. 2 is a greatly enlarged longitudinal section through a portion ofthe casing disclosed in Fig. l, illustrating one form of protectivedevice;

Fig. 3 is an enlarged longitudinal section through a portion of thecasing shown in Fig. l, disclosing another embodiment of the protectivedevice.

As disclosed in the drawing, a string of casing 10, wh-ich may besurface casing, is disposed in a previously drilled bore hole 11. Thiscasing string may constitute surface casing extending from the casingshoe 12, forming the lower terminus of the casing string, to the top ofthe well bore 11, and may include casing sections 13 threaded andcoupled to each other. This string of casing 10 may be cemented in placeby depositing cement in the annulus between it and the wall of thesurrounding well bore 11.

A hole 14 is being drilled below the string of surface 10, or othercased portion of the hole 11. A tubular drill string 15 is run throughthe string of well casing 10, this tubular drill string having a rotarydrill bit 16, `of any suitable type, secured to its lower portion foroperation upon the bottom 17 of the hole 14. The drill bit 16 drillsaway the formation material, which is flushed from the drilling regionby means of the usual rotary drilling mud pumped down through the drillstring 15 and out through fluid passages 18 in the drill bit, thedrilling mud mixing with the cuttings and carrying them upwardly aroundthe outside of the drill string 15, and through the annulus between thedrill string and the surface casing 10 to the top of the well bore. Thetubular drill string 15 may consist of sections of drill pipe secured toone another. However, as disclosed in the drawings, a string of drillcasing is attached to the drill bit 16, the drill casing includingcasing sections 19 suitably connected to each other, as through use `ofintervening casing couplings 20.

It is desired to protect the `drill string 15 and the casing 10 alreadydisposed in the well bore by preventing the drill string from rubbingagainst the inner wall of the well casing 10 during the drillingoperation. Heretofore, it has been the practice to mount rubberprotective sleeves or devices on the drill string 15 at longitudinallyspaced intervals, the rubber protectors being disposed preferably onlyupon that portion of the drill string that is located within the casedportion of the hole. The rubber protectors would bear against the innerwall of the casing 10 and prevent the steel drill string 15 itself frombearing against the latter, thus preventing wear be- -tween the Idrillstring 15 and the casing 10.

In the present instance, the protective devices are not mounted 'on thedrill string 15, but are incorporated in the casing string which hasalready been disposed in the hole, and in which the drill string isoperating.

The protective devices shown in the drawings may assume different forms.Thus, a protective device mayl be incorporated in yone or more of thecasing lcouplings Zlythat secure adjacent casing sections 13 together.`Each casing coupling 21 is of a greater length Athan is usuallyprovided, to form an extended coupling spaceZZ .between the lower end 23of the upper casing section 13 and the upper end 24l of the next lowercasing section 13 in which a'protective sleeve .25 may be disposed. Thisprotective sleeve extends along substantially the entire length of thecoupling space l22 and proiectslaterally into the casing stringhtheupper and .lower Yends 26, 2K7V of the sleeve preferably overlapping theinner walls 2850i `the upper and lower casingsections, respectively, toavoid gaps in which the drill bit ..16 might hang up or catch during,longitudinaly movement .of the latter through the casing string 10. Tofacilitate `guiding of the drill Abit 16 and other portions of the drillstring 15 past each protective device, the upper end 2'6` ofthesleeve-may flare, or be inclined, in an upward and outward direction,whereas the` lower end 17 of the sleeve may ilare, for be inclined, in adownward and outward direction. The ends. of each sleeve 25 `preferablyterminate kclosely adjacent the inner walls 28 of the upper and lowercasing section 13.

rEhe inside ydiameter of the protective sleeve 25 is materially lessthan the inside diameter of the casing sections y13 themselves. However,such inside vdiameter of the sleeve is still substantially greater thanthe outside diameter of the drill string couplings 20, to insure properannular clearance therebetween .through which the drilling mud andcuttings can pass-in an upwarddirection through the surface casing 1"0.The protective sleeve -25 is preferably made of-readily drillablematerial, such asrubber, brass, bronze, or aluminum, and is suitablysecured to the coupling member itself. If the sleeve-25 ismadeof rubberor -a'rubber-like material, it can be secured to the coupling 21bylaproper vulcaniz-ing operation. If it is=made of fbrass'onbronze, itean'beattached to the coupling21 through the use of braiing material 30.

TheA protective .device 31 disclosed near thellower end of thecasingstring`10 is secureddirectly to a casing section 13v`rather. thanto a casing collar. This protective sleeve, which may be made ofanysu-itable materiaL-such as rubber, brass, bronze or aluminum, as speciedabove, is secured to theinnerwall 28=of a .casing section,V as throughthe agency ofthe vulcanizing or brazing operationreferre'd to above,depending upon the particular material from which the protector sleeve31 is made. This'sleevehasa lesser wallfthickness thanthe other form of'protector sleeve '25, inasmuch as it is secured to the inner Ywall 28oftheY casing section, and it is preferred that 'its inside diameter 'besubstantially the same as the inside diameter of-theother protectivedevice 25. Similarly, its upper 'and lower ends 32, 33'flare inupwardand downward directions, respectively,to facilitate movementofthed'rilll 'bit 16 andthe drill string 15 therethrough. As wasdescribed in connection with"the other formofprotective device-*therewill be sufcient annular clearanceI between the drillstring land theinner wall 3d off the protective sleeve 31f for the passage of drillingmudand` cuttings therethrough. v

`The. protective devices` 1.25, 2311 are incorporated iny the surfacecasing10 or other casing run in the hole, and through 'whichl the drillstring 15 is-tol be run to Edrill a hole 142belowthe lower end of thecasing string; the protective f devices '-being longitudinally fspacedfrom one another'and'being disposed-at suitable intervals-'along thelength` of .Lthe casing stringI 10. fThe" ydrill v string 1 15 islowered through. thislcasing 10, withthe drill bit16-'at'itslower'rend,i.=the"1hole -14L1belowthe easingi string'. 10 being tion,wear between the drill string 175 and the casing 10, is prevented,inasmuch as the drill string 15 can only move laterally into engagementwith the protective devices 25, 31, and not into engagement with thecasing string 10 itself. Since the protective devices are made ofrelatively soft material as compared the steel of which the drill string15 is composed', the latter will not be subject to wea-r. Any wear thatmight take place will occur on the protective sleeve or sleevesthemselves. It is to be noted that the sleeves 25, 31-are of acomparatively large inside diameter and will lhave a relatively largewearing surface against which the drill string 15 can bear, therebyinsuring long 'life of, each protective device.

No problems are encountered in connection with the separate handling `ofsections or stands of drill pipe or drill casing 15 with protectorsthereon, inasmuch as the cased portion 10 of the hole 11 itself isprovided with the protectors. Since they drillstring 15 has noprotectors on it, there is no danger of protectors, being disposed ytheopen hole 14 below the casing string llt), which might result in theirbeing torn off, with resul-tant plugging or retarding Vof thecirculation -of the drilling mud in` an upward direction around theannulus between the drill string 15 and the casing 10; The stands ofdrill string- 15 .can be rackedland -used without regard to theprovision of protectors thereon, and it is unnecessary for carefulmeasurements to be made whenV the drill string is being run into thehole, to insure the presence of drill string protectors at the properlocation within the cased portion 10 of the hole. Actually, protectivedevices 25, 31 are disposed at they desiredv locations in casing 1t)already disposed in the holel itself.

i lt has been proposed to drill a well bore 14.- throughusc ofV casing15` asa vdrill string rather than drill pipe. The casing would be run in:the well bore and no round trips would. ever be necessary, since thedrill bit 16,is .of-.al

retrievableftype that can -be withdrawn through `the .drill casing 15without the necessity .for withdrawing .the latter at all. A vnew bitcan then be lowered through the Awell casing l5v and securedv to its.lower end. Accordingly,

sectionsof drill casing19 will be added at the top vofthe, hole .and thelatter willbey lowered in the hole 14 until, the desireddepth `ofholehas been produced. Thereafter,

the-drill bit l16`is. removed and retrieved from the .lower end ofthecasing .15 and` the latter all-owed to remain-in the'hole.

lf it were-necessary to-provide protectors on the exterior of suchadrill casing 15, the protectors would have to be incorporated thereon atthe'proper spacedintervals along itsentire length, inasmuch asprotectors di'sposedon the casing 415 within the previously casedportion '10 of the` hole will eventually be moved-down -below theylatter as drillingproceeds. Accordingly, alarge number of rubberprotectors would befoperating in o-pen hole, -where the rubberprotectors`would eventually be torn as a result of bearing against theywall-offtheopen hole ,14. Thislarge mass of ytornrubber might.completely stop they circulation of fluid, which vwould preventcontinueddrllingof the hole. Not only would sucha .condition behazardous, but the number ofprotectors required would entailconsiderableexpense.

By using an internal type of protector secured to the casing'lt),applicant avoids the necessity for mountingan excessive Anumber ofprotectors on his drillcasing 1'52 The protectors are only required inthe cased portion of the hole, and they can be `supplied, at'the desiredintervals along-the casing length whenthe casing string 10 is run in thewell bore 11.

yinasmuch as theprotective devices 25, 31 are made of readily drillablematerial, they can lbe removed by use of a suitable diameter drill bit-at anytime, which Ymight'be necessary-in the event :1an unrestrictedbore-through the casing string is desired., *The drillbit will readilydisintegrate the `rubber, brass, bronze yor aluminum 'fromwhichtheprotectorsleeves 25,531are made.

The inventor claims:

1. In combination: a string of casing disposed in a bore hole, includingcasing sections secured t-o each other, a pair of adjacent casingsections being secured to an intervening coupling, a readily drillableprotective sleeve xedly secured to said coupling and having an insidediameter sub-stantially less than the inside diameter of said pair ofcasing sections to project laterally inwardly of the inner walls of saidpair of casing sections, the upper and lower ends of said `sleeve aringin an upward direction and a downward direction, respectively, andloverlapping the walls of said pair of casing sections; a tubular d-rillstring disposed in said casing string; and a drill bit attached toReferences Cited in the file of this patent UNITED STATES PATENTS940,733 Sands Nov. 23, 1909 1,623,207 Poulsen Apr, 5, 1927 1,889,060Dennie Nov. 29, 1932 2,126,575 Ranney Aug. 9, 1938

